Method for joining a tubular metallic component within another, vertical tube, vertical tube section and comprising a first component and a second component metallic tubular metallic tubular

摘要

A method of joining one metal tubular member inside another metal tubular member such as a metal pipe 10 being joined to another metal component 12 such as a flange coupling by shrinking the outer component onto the external circumference of the pipe. The internal diameter 'B' of the outer component is initially smaller than the external diameter 'A' of the pipe, but the outer component is heated so that it expands to a diameter at which it will fit over the pipe. When the outer component is fitted over the pipe and the temperature of the outer component is allowed to cool, it will contract onto the surface of the pipe to make a permanent strong joint between the two parts. Preferably liquid nitrogen is used to cool the pipe and/or heat is used to expand the component for the pipe to be inserted. Additionally, a locking mechanism as shown in figure 5 may also be included such as a series of ball bearings inserted into a machined groove 20 via an external port 22. Preferably the method is used for to connect couplings onto the end of high pressure pipes used in deep water riser systems used in offshore oil and gas extraction.